Really fun... at first.
I must say this is a really solid effort. And it is really fun to play up until about... Day 15. At which point it becomes severely less fun and denigrates into hideously repetitive and cheap tactics just to survive because one glitch (I got hit by a headless archer who's neck was spraying blood.) and there goes half your health. Two major suggestions that I think would help. First, move the ALL the attacks off one key. For the love of god. You simply cannot buy all the attacks. It's suicide. You're forced to pick one or two moves, grab one or two pieces of armor and them dump the rest of the painfully earned gold rebuying your mercs. Second make each LEVEL harder, not each DAY. Because if you're like me, as soon as I realized there was no day limit I started hitting each and every battlefield to get gold. By time you beat the first of the bosses and reach the horsey levels, on like, day 22, maps labeled Easy are teeth grinding and ones labeled Hard are pretty much "Be prepared to lose your mercs to horsey people".
Just me $0.02